Magnetic stick type relay



FIGA.

Oct. 29, 1963 w, D, HAlLEs 1 3,109,126

MAGNETIC STICK TYPE RELAY INVENTOR.

WDHNLES HIS ATTORNEY Oct. 29, 1963 w. D. HAlLEs 3,109,126

MAGNETIC 4STICK TYPE RELAY HIS ATTORNEY United States Patent Ollce 31,109,126 Patented Oct. 29, 1963 3,109,126 MAGNETIC STICK TYPE RELAY William D. Hailes, Rochester, N.Y., assigner to General Signal Corporation, a corporation of New York Filed Dec. 9, 1959, Ser. No. 858,359 6 Claims. (Cl. 317-172) invention in general relates to electrical relays, and more particularly to the magnetic stick type of relays used in control systems for railroads.

The relays used in many of these nailway control systems must, because of the necessity for using a large number of such relays, be small and of compact construction. Furthermore, because of the fact that numbers of these relays are usually placed very near to each other on panels, it is necessary that no undesirable magnetic interference be present between adjacent relays. Such interference usually results from the existence of spurious magnetic potential differences `at Various points on the adjacent relays, other than at the working air gaps `for their respective armatures.

With the above considerations in mind, one object of my invention is to provide a magnetic stick type relay, having two -stable operational positions in accordance with the polarity of relay energizaticn, which is relatively small and of compact construction.

Another object of my invention is the provision of a relay so constructed that ythe undesirable magnetic interference between adjacent relays will be minimized.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings in which corresponding reference characters identify corresponding parts throughout the different views and in which:

FIG. 1 is an end elevation of two! identical relays, according to this invention, mounted side by side on the same base with a part shown in section to illustrate one form which the electromagnetic structure may take;

FIG. 2 is a side elevation of the relays of FIG. l;

FIG. 3 is a sectional View of the 'same relays taken along line 3 3 in FIG. 2 and viewed in the direction of the arrows;

FIG. 4 isa sectional view of the same relays taken along line 4-4 in FIG. l and viewed in the direction of the arrows;

FIG. 5 is an end elevation of la modified form of the relays of FIG. 1 with a part shown in section to illustrate another form which the electromagnetic structure may take;

FIG. 6 is -a side elevation of the relays or" FIG. 5;

FIG. 7 `is Ia sectional View of the relays of FIG. 5 and FIG. 6 taken along line 7-7 in FIG. 6` and viewed in the direction of the arrows.

Referring to FIGS. 1-4 of the accompanying drawings, one form of a relay, Iaccording 'to this invention and designated by the symbol R1, comprises la base 11 and ya nonmagnetic supporting member 12 securely attached thereto by means of bolts 13, nuts 14 and locking washers 15.

An elongated magnetizable core 16, of suitable magnetic'material such as silicon steel, and -a magnetic U- shaped strap 17, of similar material, are secured to this non-magnetic supporting member 12 with screws 18 tightly threaded into core 16. The magnetic core 16, which is shown in relay form R1 to be rectangular in cross-section, also carries a spool 19 and an associated energizable winding 20.

A permanent magnet 21k and an associated magnetic pole piece 22 are secured to the free end of core 16 with suitable adhesive cement, so as to extend in Aspace series relationship with the core 16. Furthermore, the legs of the magnetic U-shaped strap 17 extend in parallel relationship along the core `16 towards its `free end .and have their extending ends 17A bent perpendicularly towards each other in the vicinity of `the permanent magnet 21 and associated pole piece 22.

Hanging in front of pole piece 22 and the Ibent ends 17A of magnetic U-shaped strap 17 is an L-sh'aped magnetic armature 23 which is pivotally mounted on bearing plate 24 resting in slot 25 of the `armature 23. Bearing plate 24 is held securely fixed to the non-magnetic supporting member 12 and in slot 2S of the armature 23 by amature plate 26 clamped securely on it by screw 27. The lower portion of the armature 23 carries an adjustable residual screw 2.3 which is clamped in its adjusted position by nut 29. This residual screw 28 lis made of a non-magnetic material and in its adjusted position 'assists in fixing the release current of the relay R1.

The upper portion of lthe armature 23` carries an extension member 30, made of suitable insulating material, and a back-stop plate 31 which rests on the non-magnetic supporting member 12 when the rel-ay R1 is in its released position. The extension member 3d Iand the back-stop plate 31 are securely clamped to the armature 23 by rivet 32. Firmly resting on the upper portion of armature 23 is one end of a resilient kick-oit spring 33', the other end of which is tightly clamped between an L-shaped arm 34 and base 11 by screws 35. This kick-ofi spring 33 is provided to help biasv the armature 23 towards its released position, along with the relay contact load, the effectiveness of the spring being controlled by the adjustable screws 36 which are threaded through the L-shaped arm 34 and are held firmly in their adjusted position by nuts 37. An idler finger 381 is held at one end by a contract block 39, of suitable insulating material, and has its other free end extending to the top side of the non-magnetic extension member 30 lfor purposes described hereafter. Contact block 39 is securely fastened to base 11 by bolts 40.

The number` of contact fingers associated with a given relay is dependent upon the number of circuits that it must handle. As ishown here, this formof a relay possesses one row of contact fingers containing two like groups. A typical group of contact fingers includes front contact linger 41, back contact finger `42 and movable contact finger 43 attached to contact block 39* and being electrically connected to contact tips 44 which extend to the right of the contact block 39` for engagement with plug contacts lof: `a suitable plug board (not shown). Also carried by the contact block 39 are rigid stops 45` which securely hold rfront Contact fingers 41 and back Contact fingers 42 in -a fixed position.

A contact iin-ger actuating element, in the form of a contact pusher 46, is carried by the movable contact fingers 43 a-nd has its lower end resting on the non-magnetic extension member 30 for providing vertical displacement to the movable Contact fingers 43, to engage front contact fingers 41, when armature 23 is moved to its attracted position. Furthermore, movable contact fingers 43 are preformed so as to :be continually self-disposed towards the position for engagement with back contact fingers 42, when armature 23 is in its released position.

The lower portion of the contact pusher `46 is contained in a slot in the free extending end of idler finger 38` which prevents `any horizontal shifting of the lower end of contact pusher 46 while the relay Iis in operation. In addition, idler finger 38 also yaids in adjusting the rel-ay contact loading ef'lect, as desired, to provide proper relay operation.

Referring now to the aforementioned FIGS. 1-4, it is apparent that if the permanent magnet 21 is secured, at its south pole end, to the elongated core 16 and the winding is deenergized, liux emanating from the north pole end of the permanent magnet 21 flows through the pole piece 22 and returns to the south pole end of the permanent magnet 21 by Way of the main linx return path, provided `by the legs of the magnetic U-shaped strap 17, and the core 16. The major portion of this permanent magnet ux bypasses the high reluctance path offered by the armature 23 andthe two air gaps in series, when the armature 23 is in its released position, and flows directly from pole piece 22 to the bent ends 17A of the magnetic U-shaped strap 17. The remaining smaller portion of the permanent magnet liux does however traverse the air gap between pole piece 22 and the armature 23 and exerts a magnetic force on the armature 23 tending to pull the lower portion of the armature into contact with the pole piece 22 and the bent ends 17A of the magnetic U-shaped strap 17. However, the kickolf spring 33 and the relay contact load exert a larger counter acting force on the armature 23 and thereby retain the armature 23 in its released position.

If now the winding 20 is energized with a current of such polarity as to make the base end of core 16 appear as a south pole, the magnetomotive force generated in the core 16 is additive in nature with that produced by the permanent magnet 21 and the flow of magnetic flux will increase. If this current is made sufficiently large the amount of magnetic flux flowing through the high reluctance path to the armature 23 will be increased to the extent that the attractive force now acting on the armature 23 will be great enough to overcome the biasing force, produced by the kick-ofi spring 33 and the relay Contact load, and the lower portion of the armature 23 will be moved into its attracted position, bridging pole piece 22 and the bent ends 17A of the magnetic U-shaped strap 17. This movement of the armature 23 to its attracted position causes the contact pusher 46 to displace the movable contact fingers 43 in an upwardly direction for engagement with front Contact fingers 41.

Suppose now that with the armature 123 in its attracted position, the energizing pick up currentrto the winding 20 is interrupted. Because of the movement of the armature 23 to its attracted position, a very low reluctance path, through the magnetic armature 23, is now offered any magnetic iiux present, and the permanent magnet 21 now alone produces suliicient flux to exert a tractive force on the armature 23, in opposition to the counter acting biasing force, produced by =kick-olf spring 33 and the relay contact load, which is large enough to retain armature 23 in its attracted position.

However, if now a polarity of current opposite to that used to pick up the armature 23 is applied to winding 20, the base end of core 16 appears as a north pole and the magnetomotive force produced in the core 16 is in opposition to that produced by the permanent magnet 211 and the flow of magnetic lflux will be decreased. When a certain magnitude of this polarity current is reached, the resultant magnetic force on the armature 23` will be decreased to a value less than the biasing force, produced by the kick-ofi` spring 33 and the relay contact load, and the armature 23 will be urged to its released position. At the same time contact pusher 46 will be activated in a downwardly direction, by movable Contact 4fingers 43, resulting in the engagement of movable contact lingers 43 with back contact lingers 42. The armature 23 will again remain in this released position until a suilicient magnitude of pick-up current is applied to winding 20'.

The modified form of the relay according to this invention, shown in FIGS. 5-7 of the acompanying ydrawings and designated by the reference symbol R2, comprises a base 11 and a non-magnetic supporting member 12 securely fixed thereto by bolts 13, nuts 14 and locking washers 15. A magnetizable elongated core 16, shown in this form of relay as being circular in cross section and having a reduced area section 16A, and a magnetic U-shaped strap 17 are secured to the non-magnetic supponting member 12 by screw 18 which is tightly threaded into the end of the elongated core 16. The core 16 also carries a spool 19 and an associated energizable winding 2t) which is capable of magnetically saturating the reduced area section 16A of the core 16 when supplied with a relatively high degree of applied electrical energy.

A permanent magnet 21 and an associated magneti-c pole piece 22 are attached to the free end of core 16, with suitable adhesive cement, so as to extend in space series relationship with the core 16. Furthermore, the legs of lthe magnetic U-shaped strap 17 extend in parallel relationship along the core 16 and have their extending ends 17A bent perpendicularly towards each other in the vicinity of the permanent magnet 21 and the associated pole piece 22.

A non-magnetic L-shaped armature support 23A, having cemented to it a small magnetic armature piece 23 which is only large enough to coact with and properly cover the working pole-faces of the relay, is pivotally mounted on kbearing plate 24 resting in slot 25 of the non-magnetic anmature support 23A so that the magnetic armature piece 23 -hangs in front of the magnetic pole piece 22 and the ben-tends 17A of the magnetic U-shaped strap 17. Furthermore, the hanging portion of armature support 23A is bent slightly towards the core structure of the relay R2 to assure a fiat contact between armature piece 23 and pole piece 22 and between armature piece 23 and the bent ends 17A of the magnetic U-shaped strap 17, when the armature piece 23 is in its attracted position. Bearing plate 24 is securely held to the non-magnetic supporting member 12 and in slot 25 of the non-magnetic armature support 23A by armature plate 26 which rests firmly upon it and is held thereon by `screw 27 which is tightly threaded through the non-magnetic supporting member 12. Also, the air gap side of the larmature piece 23 is plated with a non-magnetic material, such as chrome, to provide the `desired residual gap between armature piece 23 and the pole .piece 22 and between armature piece 23 and the lbent ends 17A of the magnetic U-shaped strap 17, when the armature piece 23 is in its attracted position. f

Securely fastened to the upper portion of the nonrnagnetic armature support 23A, by rivet 32, are extension member 3), of suitable insulating material, and backstop plate 31 which positively defines the released position of armature support 23A.

Two resilient biasing fingers 38 are firmly attached at one end to contact blocks 39, of suitable insulating material, and have their extending free ends resting on the non-magnetic extension member 30 for the purpose of continually disposing, as desired, the non-magnetic 1arrnaturefsupport 23A towards its releasedV position.

Contact blocks 39, which are secured to the base 11 by bolts 40, also carry the desired contact fingers of the relay R2 and as shown, a typical group of contact lingers includes front Contact finger 41, back Contact finger 42 and movable contactiinger 43 which are electrically connected to the contact tips 44 which extend to the right of the contact blocks 39 for engagement with plug contacts of a suitable plug board (not shown). Rigid stops 45 are also held by contact blocks 39 and extend along front contact lingers 41 and back contact fingers 42 to hold these contact ngers in a rigid stationary position.

Contact pushers 46, of suitable insulating material, are carried by movable Contact fingers 43 and have their lower portion resting on the non-magnetic extension member 30 for providing vertical displacement to the movable contact fingers 43 to carry them 'into engagement with front contact lingers 41 when the non-magnetic armature support 23A is moved to its attracted position.V The engagement of movable contact fingers 43 with back contact fingers 42, when armature support 23A is in its released posit-ion, is effected by the downward biasing force which is trapped into the movable contact lingers 43 by preforming before assembly. In addition, the lower portion of contact pushers 46 are contained in .slots in the associated idler lingers 38, thus preventing any horizontal shifting of the lower end of contact pushers 46 while the relay R2 is in operation.

Referring again to FIGS. 5-7 of the accompanying drawings, if it is assumed that winding 20 is deenergized and that the permanent magnet 21 is attached, at its south pole end, to the magnetizable core 16, it is apparent that the magnetic iiux emanating from the north pole end of the permanent magnet 21 flows through the magnetic pole piece 22, and divides with the major portion of the magnetic liux flowing directly to the bent ends 17A of the magnetic U-shaped strap 17 and only a relatively small amount of flux traversing the high reluctance air gap path in series with the magnetic armature piece 23, The total magnetic flux then returns to the south pole end of the permanent magnet 21 by flowing through the low reluctance liux path provided by the legs of the magnetic U-shaped strap 17 and the magnetizable core 16. The liow of the smaller portion of llux across the relay air gap to the magnetic armature piece 23 exerts a force on the magnetic armature piece 23 which tends to draw the non-magnetic armature support 23A into its attracted position, with the magnetic armature piece 23 bridging the magnetic pole piece 22 and the bent ends 17A of the magnetic U-shaped strap 17. However, the relay -contact load and the resilient biasing fingers 38 produce a greater counter acting force on the non-magnetic armature support 23A and thereby retain the non-magnetic armature support 23A and the associated magnetic armature piece 23 in their released position.

If now winding 20 is energized with a polarity of current such that the lmagnetomotive force thereby produced in the core 16 is additive in nature with that produced by the permanent magnet 21, the total magnetic flux present is increased with a corresponding increase in the amount of flux that flows across the relay lair gap to the magnetic armature piece 23. The resulting magnetic force on the armature piece 23 will now be sufcient to overcome the restraining force, produced by the relay contact load and the resilient biasing lingers 38, and the non-magnetic armature support 23A will be drawn into its attracted position, with the magnetic armature piece 23 bridging the magnetic pole piece 22 and the bent ends 17A of the magnetic U-shlaped strap 17. This pivoted movement of the non-magnetic armature support 23A into its attracted position imparts an upward vertical displacement to the contact pushers 46 and carries movable contact lingers 43 into engagement with front contact lingers 41. Also, because of the movement of the magnetic armature piece 23 to its attracted position the leakage paths from the pole piece `22 to the bent ends 17A of the magnetic "U-shaped strap 17 are now shunted and the magnetic reluctance of the resulting main relay flux path is suliiciently reduced so that the permanent magnet 21 now alone produces the amount of flux needed to produce a sufficient magnetic force on the magnetic armature piece 23, in opposition to that restraining force, produced by the relay contact load and the resilient bias-ing lingers 38, to retain the magnetic armature piece 23 in its attracted position.

However, if now the winding 20 is energized with the opposite polarity current such that the magnetomotive force produced in the core 16 is in opposition to that produced by the permanent magnet 21, the total flux flowing across the residual air gaps is decreased and the resulting magnetic force on the armature piece 23 will be ineffective against the restraining force, produced by relay contact load and the resilient biasing fingers 38, and the nonmagnetic armature support `23A and armature piece 23 will be returned to their released position and will remain there until winding 20 is energized with a suliicient magnitude of pick-up polarity current. Concurrent with this releasing of the non-magnetic armature support 23A will be the activation of contact pushers 46 in a downwardly direction which carries movable contact fingers 43 into engagement with back contact lingers 42.

It is apparent that if the release polarity current is increased in magnitude Without restraint, the magnetic field produced by this current may become sufficiently strong to demagnetize the permanent magnet 21. To obviate this detrimental tendency, the reduced area section 16A is provided, on core 16, which magnetically saturates on relatively high degrees of applied energization to winding 20, thereby setting a limit on the amount of flux that may flow in the magnetic lcircuit of the relay and thereby also protecting the permanent magnet 21 against possible demagnetization.

By reierence to the accompanying drawings and the foregoing description, it can be seen that a rel-ay, small and of compact construction, is provided that may assume either of two stable operational positions, depending upon thepolarity of the energizing current to the relay, and which will remain in either of these positions until actuated to the other by application of an opposite polarity current.

As stated previously, in relay system operation, undesirable magnetic interference exists between closely spad relays and usually results from the presence of spurious magnetic potential differences scattered over the exterior of these adjacent relays of the system. In the relay structures described there are no large magnetic potential differences anywhere on the exterior of the relay that might effect adjacent relays. In the energized position those potential differences that do exist are enclosed and Well shrouded by the magnetic main liux return path. In the released position, some magnetic potential differences do occur at the air gaps of the relay but these are well shrouded by the armature and exist only at the end of the relay, where they are usefully employed, and not at the sides of the relay structure where they could aliect adjacent relays. Therefore, it is apparent that a relay is provided which is so constructed that undesirable magnetic interference between adjacent relays will be min-imized.

Having described an electrical relay and `a modification thereof, as specitic embodiments of the present invention, it is desired `to be understood that these forms are selected (to facilitate in the disclosure of the invention rather than -to limit the number of forms `which it may assume; and, it is to be further understood Ithat various other modilications, adaptations and alterations may be applied to the specific yforms shown to meet the requirements of practice, without in any manner vdeparting from the spirit or scope of the present invention.

hat I claim is:

l. A relay including an electromagnet, a permanent magnet secured to one `end of and Iextending in space series relationship with said electromagnet, a magnetic U-shaped strap secured to the other end of said electrolmagnet and having its klegs extending in parallel relationship with said electromagnet towards said permanent magnet for providing the main flux return path between sai-d permanent magnet and said electromagne-t, and an armature capable of bridging said permanent magnet and said U-shfaped strap when in its attracted position.

2. A relay as specified in claim 1 wherein the extending legs 'off said magnetic U-shaped strap `are bent perpendicularly toward each other adjacent said permanent magnet, whereby said armature bridges said permanent magnet and the 'bent ends :of said magnetic U-'shaped strap when the Iarmature is in its attracted position.

3. A relay comprising an electromagnet having a core structure and `an energizable winding, a nonmagnetic member secured to `one end of said core structure land extending towards bult spaced from the free end of said core structure, la permanent magnet secured to the free end of Isaid core structure and extending in space series relationship therewith, a magnetic member secured to the fixed end of said core structure and having its own free extending end adjacent said permanent magnet, `and an armature structure pivotally mounted on the extending portion of said nonmagnetic member and having a portion for bridging said permanent magnet and the free extending end of said magnetic member when said armature structure is in its attracted position, said magnetic member acting as the main ilux return path lbetween said penmanent magnet and said core structure.

4. A relay `as specied in claim 3, wherein said armature structure is constructed mainly of nonmagnetic material and only fthe bridging portion thereof is made of magnetic material.

5. A relay as specified in claim 3, wherein the core structure ot said electromagnet has a reduced area section which becomes magnetically saturated for relatively large magnitudes ot energizing current to said energizable windL lng.

6. A relay comprising an electromagnet, a permanent magnet secured to one end of said electromagnet and extending in space series relationship therewith, a magnetic U-shaped strap secured at its center pontion to the opposite end -of said electromagnet and having its legs exmanent magnet, and an armature structure pivotally Imounted on the free end olf said nonmagnetic member for bridging said permanent magnet and the extending legs of said U-shaped strap when said armature structure is in its attracted position.

References Cited in the le of this patent UNITED STATES PATENTS 1,958,640 Reynolds May 15, 1934 2,170,694- Penry Aug. 22, 1939 2,307,922 Dichten Jan. 12, 1943 2,355,543 Martin Aug. 8, 1944 2,375,017 Marrison May l, 1945 2,853,659 Hen'on Sept. 23, 1958 2,869,050 Van Urk et al Jan. 13, 1959 

1. A RELAY INCLUDING AN ELECTROMAGNET, A PERMANENT MAGNET SECURED TO ONE END OF AND EXTENDING IN SPACE SERIES RELATIONSHIP WITH SAID ELECTROMAGNET, A MAGNETIC U-SHAPED STRAP SECURED TO THE OTHER END OF SAID ELECTROMAGNET AND HAVING ITS LEGS EXTENDING IN PARALLEL RELATIONSHIP WITH SAID ELECTROMAGNET TOWARDS SAID PERMANENT MAGNET FOR PROVIDING THE MAIN FLUX RETURN PATH BETWEEN SAID PERMANENT MAGNET AND SAID ELECTROMAGNET, AND AN ARMATURE CAPABLE OF BRIDGING SAID PERMANENT MAGNET AND SAID U-SHAPED STRAP WHEN IN ITS ATTRACTED POSITION. 